Outlook: The 49ers have the most explosive tight end in the NFL. Davis averaged 16.3 yards per catch in 2013, which was higher than Jimmy Graham's, Rob Gronkowski's and Jordan Cameron's averages -- higher, in fact, than any full-time tight end's in the league.

The problem for the 49ers is that Davis was alone. He was the only deep threat in the 49ers' pass-catching arsenal, and the teams that faced San Francisco in the playoffs adjusted accordingly. Davis caught two touchdowns in the three contests, but he averaged just 18 receiving yards a game as defenses made sure to keep a safety on top of him throughout. By contrast, Davis averaged 85 receiving yards a game in the 2012 playoffs and 146 yards a game in the 2011 playoffs.

In previous seasons, if a defense concentrated on Davis, the 49ers quarterback had a trusty secondary target to which to throw, Delanie Walker. He was on the field for 529 snaps through the NFC Championship game in 2012 and finished with 429 yards and three touchdowns through that game. Walker is in Tennessee now. (He finished 10th in the league among tight ends with 60 receptions in the regular season, eight more than Davis. However, the latter had more receiving yards - 850 to 571 - and touchdowns - 13 to 6).

Walker's replacement, second-round pick McDonald, played nearly as many snaps, 480, in 2013 as Walker did last season but finished with only eight catches for 118 yards. Walker's former role was filled more by fullback Bruce Miller, who was the team's third-leading pass catcher when he was lost for the season with a broken scapula in December. His loss was mitigated by the fact that receiver Michael Crabtree was just then recapturing his 2012 form. Still, Walker left a gap in the team's attack that never was fully filled.

McDonald was in on roughly half of the 49ers' offensive snaps during the season and in the playoffs. He was by no means as valuable a blocker as Walker was in previous seasons, but he improved in that regard as the season went on. The rookie was making a quantum leap from the spread-style offense he ran at Rice to a power-based NFL system, something that must be taken into account when looking at his meager numbers. But so was former Rice teammate Luke Willson, a fifth-round pick at tight end who finished with 20 catches, 272 yards and a touchdown for the Seahawks.

Youth watch: The 49ers signed Seahawks draft pick Chris Harper with the thought they could turn him into a Walker-type tight end. That experiment, however, fizzled and Harper was cut and signed by Green Bay in October. The 49ers then acquired another former receiver in Carrier. He turned heads at his Beloit College pro-day workout in 2012 when he ran his 40-yard dash in less than 4.5 seconds, had a 40-inch vertical jump, a 10-foot, 2-inch broad jump and sped through the three-cone drill in 6.69 seconds. To put that three-cone time in perspective: Just one receiver at the combine that year had a better mark.

Carrier is up to 250 pounds as he makes the transition to tight end. He played 41 snaps in 2013, most of them coming when No. 3 tight end Celek was out with an ankle injury at midseason. Carrier is not much of a blocker, but at this stage in his career, neither was Walker. Carrier promises to see a lot of snaps this spring and summer and should be interesting to watch.

Bottom line: The 49ers are committed to a two-tight end offense but only got real production from one tight end in 2013. McDonald certainly is not a bust. But he must tap his potential in 2014. After using a second-round pick on McDonald last year, the 49ers are unlikely to grab a tight end high in the draft in May. But they could use a late-round pick at the position.

MATTHEW BARROWS

Matt was born in Blacksburg, Va., and attended the University of Virginia. He graduated in 1995, went to Northwestern for a journalism degree a year later, and got his first job at a South Carolina daily in 1997. He joined The Bee as a Metro reporter in 1999 and started covering the 49ers in 2003. His favorite player of all time is Darrell Green.